Batboard

Have a couple of CDM1250's with TX power out put in the 1.5watt to 4watt range. Is there a usual suspect that needs replacing when this happens, or is it time to ship it to the depo for a $285 bill?

I do have CPS for these and tuner software, but i'm not sure how to set/check PA , battery voltage,ect on these.

I know about the "power pad", and its not that.

What model/band are they?

It could be the RF PA transistor/s. How many there are and how much trouble they are to replace depends on the model. It also requires adjusting the bias and recalibrating the power, which can be a bit tricky.

You can try hooking a radio up to a wattmeter/service monitor, then going into the Tuner software, read the radio with it and go to Tx Align/K&M Tuning. Click your mouse in one of the high power boxes to select it and click Toggle PTT, if you get normal output power with that then it's not the transistors.

Jack thank you. I read the radio with tuning software and went into the K&M tuning section, selected one of the High pwr boxes and saw only about 1.5watts when it should be 23watts or so according to the box selected. The low pwr box on that particular freq was like .4watts or so. So it is one of the transistors in between Q3441 and the RF ouput antenna switch, given in the manual. Or I guess I start from there anyways. I was just hopeing there was a particular component that likes to go bad.

Hmm, do I replace them all ( shotgun? ) or are there too many of them (Motorola depo)?

Honestly unless you're a whiz with a soldering iron and have all the equipment needed to retune you are probably best off going the flat rate route. I'd bet you're looking at about $200 in parts and labor per radio at the local shop, for about $50 more you could send it in for a flat rate and Motorola's awesome depot would be more likely to replace the entire mainboard than just the transistors. Plus they warranty the whole unit for 90 days, not just the repair they performed. So if the LCD craps out 2 weeks for example later you're covered

escomm wrote:Honestly unless you're a whiz with a soldering iron and have all the equipment needed to retune you are probably best off going the flat rate route. I'd bet you're looking at about $200 in parts and labor per radio at the local shop, for about $50 more you could send it in for a flat rate and Motorola's awesome depot would be more likely to replace the entire mainboard than just the transistors. Plus they warranty the whole unit for 90 days, not just the repair they performed. So if the LCD craps out 2 weeks for example later you're covered

I was hopeing that maybe there were only a few small parts that were usual suspects that were resposible and I could solder my way thru a relatively easy repair. I've been able to replace some small parts like fuses on PR400 and HT1250 portables and such, eh, they might be a little crooked...ha.

Ok, off to the depot I guess.

It's usually the output transistor that goes bad, usually from transmitting into a bad antenna. If you have the radios I think you do, it's a surface mount LDMOS transistor. You need to be pretty good with an iron to do those, depot is probably a good choice.

After they're repaired make sure you check the antennas when you hook them back up.

Ok, thanks! Maybe I'll give one a shot and see how it fares. I think I have a decent cadaver here I can practice on.